Winter vegetable oils and process of preparing the same



Patented July 21, 1953 UNITED STATES PATENT OFFICE.

WINTER VEGETABLE OILS AND PROCESS OF PREPARING THE S AME Harvey l). Royce, Savannah, Ga., assignor to The Southern Cotton Oil Company, Savannah, Ga., a corporation of New Jersey No Drawing. Application July 28, 1951,

' Serial No. 239,187

6 Claims. 1

, acids, which comprise the bulk or" the solid glycerides referred to in the trade as stearin. The

stearin which separates from vegetable oils upon chilling may also contain some of the more insoluble non-glyceride constituents of the oils, such as waxes, sterols, higher alcohols and phosphatides.

More specifically, this invention relates to retarding the clouding and deposition of stearin in salad oils, particularly winter cottonseed oil, and which may be defined more broadly as including any refined vegetable oil which does not deposit stearin on long standing at temperatures substantially above the range of temperatures herein after specified. During prolonged exposure to refrigeration or severe winter climatic temperatures in the range from 32 to 45 F., many salad oils lose their clarity and brilliancy owing to separation of stearin, and while this does not render the oils unfit for edible purposes, it detracts from their appearance. Moreover, the stability of a mayonnaise or salad dressing emulsion against separation upon exposure to freezing temperature is to a large extent dependent upon the resistance of the salad oil component to clouding and stearin separation. A well known and standardized procedure used in the salad oil trade for evaluating the resistance of an oil to clouding, commonly referred to as the cold test, consists in aging a care- 2 percentage of aluminum tristearate, and such winter vegetable oil was described and claimed in a patent issued to me April 8, 1947, No. 2,418,668. At that time I considered zirconium soap to be a probable equivalent of aluminum stearate. I have since discovered, by actual test, that clouding of a'salad oil, upon exposure to cold storage temperatures, can be inhibited strongly by incorporating therein fractional percentages of zirconium or zirconyl soaps of solid saturated fatty acids, such as behenic, palmitic,

, stearic, and arachidic acids, or mixtures thereof.

I have also discovered that zirconium, and more particularly any of the zirconyl soaps of solid saturated fatty acids, preferably'zirconium stearate, is unique among metal soaps in having an apparent antioxidant action on fats and oils, since most oil-soluble metal compounds accelerate the development of rancidity. Zirconium stearate is comparatively tasteless, odorless, and nontoxic, and small amounts are not objectionable in edible oils.

By way of example, to a winter cottonseed salad oil having a cold test of 20 hours was added 0.05 per cent. of zirconyl stearate, and after heating the mixture to dissolve the stearate and drive off the moisture, a sample of the treated oil remained clear and free from cloud after 90 hours soap were dissolved in'1400 parts of water and to this solution was added slowly, while stirring,

fully dried sample of the oil in a bath of crushed ice and water at 32 F. and noting elapsed time until a cloud or deposit of stearin is visible. The efiectiveness of any inhibitor is determined by a comparison of such elapsed time when chilling the treated oil with the elapsed time when chilling the untreated oil. A secondary factor in determining the effectiveness of the inhibitor is the amount of clouding or deposit when the cooling period is further prolonged.

A number of years ago I discovered that a winter vegetable oil having sufficient resistance to clouding and stearin separation to withstand a cold test of at least twenty-four hours could be produced by colloidally dispersing therein a small at 4'5 C., 100 parts of a 5% solution of zirconium tetrachloride. The finely divided suspension of zirconium soap was 'coagulated by diluting the suspension with an equal volume of water, and the resultant precipitate was filtered, washed, and dried in vacuo at 40 C. The product was a yellowish white powder, easily soluble in hot vegetable oil, and contained 9.93% zirconium by 7 analysis.

While thepresent invention is not limited to acid soap is formed, e. g., one which contains a slight excess of fatty acid. An alternative method of forming the zirconium soap comprises heating organic salts of zirconium, such as the acetate, with stearic acid. Effective cloud inhibitors have also been prepared by adding a concentrated, slightly acid solution of zirconyl sulphate to a warm dilute solution of potassium stearate.

The percentage of zirconium or zirconyl soaps of solid saturated fatty acids that should be added should notbe less than about .01%, but should preferably be from .03 to .08 per cent, say .05 per cent. A considerably larger proportion is permissible, but should not substantially exceed 0.2

The zirconium soaps of this invention, while described broadly as soaps of solid saturated fatty acids, may contain minor amounts of liquid unsaturated fatty acids, such as oleic, linoleic, and linolenic acids, up to an amount of 20 to 30 per cent, Without seriously affecting the cloudinhibiting power of the product. Likewise the presence of small amounts of solid unsaturated fatty acids, such as iso-oleic acid, is allowable.

What is claimed is:

1. A vegetable salad oil in which the resistance to clouding and solidification at freezing tem perature has been enhanced by the incorporation therein of a small percentage of one or more materials selected from the group consisting of zirconium and zirconyl soaps of solid saturated fatty acids.

2. The winter vegetable oil according to claim 1 in which the percentage of the incorporated material is within about the range 0.1 to 0.2 per cent.

3. The winter vegetable oil according to claim 1 in which the incorporated material is selected from the group consisting of zirconyl soaps of solid saturated fatty acids.

4. The winter vegetable oil according to claim 1 in which the incorporated material is a zirconium soap of stearic acid.

5. The process of inhibitin the clouding of winter vegetable oils at freezing temperatures which comprises adding thereto a small percentage of one or more materials selected from the group consisting of zirconium and zirconyl soaps of solid saturated fatty acids.

6. A winter vegetable oil in which the resistance to clouding and stearine deposition at 32 F. has been enhanced by the incorporation therein of a fractional percentage of one or more materials selected from the group consisting of zirconium and zirconyl soaps of predominantly saturated fatty acids, said material having an antioxidant action on the oil, and adequate to enable the oil to withstand a cold test not less than double that of the untreated oil.

HARVEY D. ROYCE.

References Cited in the file Of this patent UNITED STATES PATENTS Number Name Date 2,079,336 Ralston et al May 4, 193'? 2,320,319 Black May 25, 1943 2,e18,668 Royce Apr. 8, 1947 

1. A VEGETABLE SALAD OIL IN WHICH THE RESISTANCE TO CLOUDING AND SOLIDIFICATION AT FREEZ/NG TEMPERATURE HAS BEEN ENHANCED BY THE INCORPORATION THEREIN OF A SMALL PERCENTAGE OF ONE OR MORE MATERIALS SELECTED FROM THE GROUP CONSISTING OF ZIRCONIUM AND ZIRCONYL SOAPS OF SOLID SATURATED FATTY ACIDS. 